The Gem razor is the Featherweight and it is one of the later razors manufactured in the late 50's. It was the razor I learned to shave with and is considered to be a good introduction to the Gem types. It is light, very forgiving and on the mild side, but gives a great shave. As a beginner, I would start off with a Personna stainless Steel blade as it won't rust if you leave it in the razor. As for advice, just start off with the angle that the head gives you and go slow at first until you learn the characteristics of it. Don't apply any pressure as the blade is stiffer than a DE and is not as forgiving if too much pressure is applied.
Just remember to have fun.
Oh, and the Techmatic, remove the cartridge and wrap the razor and cartridge separately in tissue paper and put it where nobody can find it. You don't want someone to come across it and try to shave with it.